O.S. Speed R2102 .21 On-Road 1/8 Scale Racing EFRA

Tower Stock# OSMG2048  •  Manufacturer Stock# 1A100
O.S. Speed R2102 .21 On-Road 1/8 Scale Racing EFRA (large view)
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Notes from our tech department:
This is the O.S. Speed .21 R2102 Engine for On-Road 1/8 scale Racing.


Compatible with 16% nitro fuel, which complies with EFRA regulations
Second inner button head allows for finer tuning to meet track
New ceramic rear crankshaft ball bearing
Tungsten weighted and silicone filled crankshaft
Slide valve carburetor
8.5mm reducer installed in carburetor venturi to reduce amount of
air flow for greater torque


O.S. Speed R2102 Engine, 8.5mm Carb Reducer, Inner Head, T-RP7 Plug,
Exhaust Seal Ring, Tapered Collet, two Carb Dust Seal Caps and


Fuel: 10-30% nitro content, 20% recommended for break-in
Glow starter and track equipment


Carburetor Settings;
Needle Valve: Three turns open from fully closed position
Mixture Control Valve: Flush with carburetor body, adjusting range
+/- 1 turn
Metering Needle: Flush with ball link body
Throttle Stop Screw: 0.5mm from side of carburetor body when
viewed from above

Displacement: .213 cu in (3.49 cc)
Bore: 0.633 in (16.08 mm)
Stroke: 0.677 in (17.2 mm)
Practical RPM: 4,000-45,000
Power Output: 2.8 ps/2.76 hp @ 33,000 rpm
Weight: 11.99 oz (340 g)
Crankshaft Size: UNF1/4-28
Distance Between Mounting Holes Same Side: 0.83" (21mm)
Distance Between Mounting Holes Opposite Side: 1.45" (37mm)
Height Bottom of Mounting Tabs/Top of Cylinder Head: 2.9" (75.6mm)
Height Bottom of Mounting Tabs/Center of Exhaust Outlet: 1.1" (28mm)
Width of Mounting Tabs: 1.8" (45mm)
Distance from Backplate to Front Bearing: 2.5" (64.5mm)
Distance from Center of Crankcase to Front Bearing: 1.7" (44mm)
Distance from Center of Crankshaft to Backplate: 0.81" (20.5mm)

jxs 11/02/15

See Tower Catalog page 172.
Easy RC: Engines
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